Enhanced carbon utilization and storage: An application of nonionic-based binary surfactant CO₂ foam

Mobility control of CO₂ is important for effective subsurface utilization and sequestration of anthropogenic CO₂ in depleted formations. This not only enhances oil recovery but also increases CO₂ storage efficiency, addressing a key challenge for a future zero-carbon economy. In this study, novel techniques were developed by injecting CO₂ foam generated with a nonionic-based binary surfactant system to improve geological CO₂ storage and to co-optimize carbon utilization and storage efficiency in high salinity carbonate porous media, based on hypotheses from our previous works. Carbonate core samples from a producing oil field were used as the porous media to evaluate oil production and CO₂ storage with varying injectants. The introduction of foam as a mobility control fluid significantly increased the CO₂ retention factor by 4.6 times. With the addition of a nonionic-based binary surfactant system as a foaming agent, the retention factor further increased to 5.6 times. This is in addition to an 85% increase in oil recovery. This study demonstrates the potential of surfactant foams to control the mobility of injected gas, thereby enhancing CO₂ retention in carbonate porous media. The findings highlight the effectiveness of nonionic-based binary surfactant systems as foaming agents for the co-optimization of carbon utilization and storage in depleted oil formations.